Method and apparatus for data modulation and coding for new radio

ABSTRACT

Provided is a method of transmitting scheduling control information on a physical uplink shared channel by a base station. The method includes transmitting control information indicating a specific modulation and coding scheme (MCS) index corresponding to modulation and coding scheme (MCS) information to be applied to the physical uplink shared channel through a physical downlink control channel, and receiving the physical uplink shared channel modulated based on specific MCS information determined using one of two or more MCS tables containing the specific MCS index and modulation order information corresponding to at least the MCS index.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Applications No.10-2018-004091, filed on Jan. 11, 2018, No. 10-2018-0058965, filed onMay 24, 2018, & No. 10-2018-0132306, filed on Oct. 31, 2018 which arehereby incorporated by reference for all purposes as if fully set forthherein.

BACKGROUND OF THE DISCLOSURE Technical Field

The present disclosure relates to methods and apparatuses fortransmitting and/or receiving control information through a physicaldata channel in a next-generation/5G radio access network (hereinafter,referred to as a new radio (NR)).

More specifically, the present disclosure proposes methods of datamodulation and coding for satisfying requirements of reliability forultra reliable and low latency communications (URLLC) data.

Background Art

Recently, the 3rd generation partnership project (3GPP) has approved the“Study on New Radio Access Technology”, which is a study item forresearch on next-generation/5G radio access technology. On the basis ofthe Study on New Radio Access Technology, Radio Access Network WorkingGroup 1 (RAN WG1) has been discussing frame structures, channel codingand modulation, waveforms, multiple access methods, and the like for thenew radio (NR). The NR is required to be designed not only to provide animproved data transmission rate as compared with the long term evolution(LTE)/LTE-Advanced, but also to meet various requirements in detailedand specific usage scenarios.

An enhanced mobile broadband (eMBB), massive machine-type communication(mMTC), and ultra reliable and low latency communication (URLLC) areproposed as representative usage scenarios of the NR. In order to meetthe requirements of the individual scenarios, it is required to designframe structures to be more flexible, compared with theLTE/LTE-Advanced.

Particularly, there is an increasing need for a specific and efficientmethod of defining a separate modulation and coding scheme (MCS) tablefor each target block error rate (BLER) in the NR.

SUMMARY

To address such issues, at least one object of the present disclosure isto provide methods and apparatuses for defining a separate MCS table foreach target BLER in the NR.

In accordance with an aspect of the present disclosure, a method of abase station is provided for transmitting scheduling control informationon a physical uplink shared channel.

The method of the base station includes transmitting control informationindicating a specific modulation and coding scheme (MCS) indexcorresponding to modulation and coding scheme (MCS) information to beapplied to a physical uplink shared channel through a physical downlinkcontrol channel, and determining specific MCS information used for thephysical uplink shared channel using the specific MCS index and one oftwo or more MCS tables containing modulation order information andtarget code rate corresponding to at least the specific MCS index.

In accordance with another aspect of the present disclosure, a method ofa user equipment is provided for receiving scheduling controlinformation on a physical data channel.

The method of the user equipment includes receiving control informationindicating a specific modulation and coding scheme (MCS) indexcorresponding to modulation and coding scheme (MCS) information to beapplied to a physical data channel through a physical downlink controlchannel, and determining specific MCS information used for the physicaldata channel using the specific MCS index and one of two or more MCStables containing modulation order information and target code ratecorresponding to the specific MCS index.

In accordance with another aspect of the present disclosure, a basestation is provided for transmitting scheduling control information on aphysical uplink shared channel.

The base station includes a transmitter configured to transmit controlinformation indicating a specific modulation and coding scheme (MCS)index corresponding to modulation and coding scheme (MCS) information tobe applied to a physical uplink shared channel through a physicaldownlink control channel, and a receiver configured to receive thephysical uplink shared channel modulated based on specific MCSinformation determined using the specific MCS index and one of two ormore MCS tables containing modulation order information and target coderate corresponding to the specific MCS index.

In accordance with another aspect of the present disclosure, a userequipment is provided for receiving scheduling control information on aphysical data channel.

The user equipment includes a receiver configured to receive controlinformation indicating a specific modulation and coding scheme (MCS)index corresponding to modulation and coding scheme (MCS) information tobe applied to a physical data channel through a physical downlinkcontrol channel, and a controller configured to determine specific MCSinformation used for the physical data channel using the specific MCSindex and one of two or more MCS tables containing modulation orderinformation and target code rate corresponding to the specific MCSindex.

In accordance with embodiments of the present disclosure, it is possibleto define a separate MCS table for each target BLER in the NR.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a structure of a NRwireless communication system.

FIG. 2 is a diagram illustrating a frame structure of a NR system.

FIG. 3 is a diagram illustrating a resource grid supported by radioaccess technology.

FIG. 4 is a diagram illustrating a bandwidth part supported by radioaccess technology.

FIG. 5 is a diagram illustrating an exemplary synchronization signalblock in radio access technology.

FIG. 6 is a diagram illustrating a random access procedure in radioaccess technology.

FIG. 7 is a diagram illustrating control resource sets (CORESETs).

FIG. 8 is a diagram illustrating a comparison between a subslot and aslot.

FIG. 9 is a diagram illustrating that a user equipment using a RLLCservice preempts a resource allocated to a user equipment using an eMBBservice.

FIG. 10 is a diagram illustrating a transmission block configuration forsupporting code block group based retransmission.

FIG. 11 is a flow chart illustrating a method of a base station fortransmitting control information on a physical uplink shared channelaccording to an embodiment of the present disclosure.

FIG. 12 is a flow chart illustrating a method of a user equipment forreceiving control information on a physical data channel according to anembodiment of the present disclosure.

FIG. 13 is a block diagram illustrating a base station according to anembodiment of the present disclosure.

FIG. 14 is a block diagram illustrating a user equipment according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In denoting elementsof the drawings by reference numerals, the same elements will bereferenced by the same reference numerals although the elements areillustrated in different drawings. In the following description of thepresent disclosure, a detailed description of known functions andconfigurations incorporated herein will be omitted when it is determinedthat the description may make the subject matter of the presentdisclosure rather unclear.

Terms, such as first, second, A, B, (a), or (b) may be used herein todescribe elements of the disclosure. Each of the terms is not used todefine essence, order, sequence, or number of an element, but is usedmerely to distinguish the corresponding element from another element.When it is mentioned that an element is “connected” or “coupled” toanother element, it should be interpreted that another element may be“interposed” between the elements or the elements may be “connected” or“coupled” to each other via another element as well as that one elementis directly connected or coupled to another element.

In addition, terms and technical names used herein are for the purposeof describing specific embodiments, and technical spirit of the presentdisclosure is not limited to the corresponding terms. Unless definedotherwise, the terms described below may be construed in a mannernormally understood by any person skilled in the art to which thepresent disclosure pertains. In a case where a corresponding term is amisleading technical term that does not precisely embody the technicalspirit of the present disclosure, it should be understood that the termis replaced by a technical term that can be correctly understood by anyperson skilled in the art. Further, the terms used in the presentdisclosure should be construed as according to definitions indictionaries or context, and should not be construed as beingexcessively reduced in meaning.

In the present disclosure, the wireless communication systems refer tosystems for providing various communication services using radioresources, such as a voice service, a data packet service, etc., and mayinclude a user equipment, a base station, and a core network.

Preferred embodiments described below may be applied to wirelesscommunication systems using various radio access technologies. Forexample, embodiments of the present disclosure may be applied to variousmultiple access techniques, such as code division multiple access(CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), singlecarrier frequency division multiple access (SC-FDMA), orthe like. The CDMA may be implemented with radio technologies, such asuniversal terrestrial radio access (UTRA) or CDMA2000. The TDMA may beimplemented with radio technologies, such as global system for mobilecommunications (GSM), general packet radio service (GPRS), enhanceddatarates for GSM evolution (EDGE). The OFDMA may be implemented withradio technologies, such as institute of electrical and electronicsengineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20,evolved UTRA (E-UTRA), or the like. The IEEE 802.16m is an evolution ofIEEE 802.16e and provides backward compatibility with systems based onIEEE 802.16e. The UTRA is a part of the universal mobiletelecommunications system (UMTS). 3rd generation partnership project(3GPP) long term evolution (LTE) is a part of E-UMTS (evolved UMTS)using evolved-UMTS terrestrial radio access (E-UTRA), and uses the OFDMAin downlink and the SC-FDMA in uplink. As described above, embodimentsof the present disclosure may be applied to radio access technologiesthat are currently being launched or commercialized, or that are beingdeveloped or developed in the future.

Meanwhile, in the present disclosure, a user equipment is defined as ageneric term meaning a device including a wireless communication moduleperforming communications with a base station in a wirelesscommunication system. The user equipment shall be construed asincluding, but not limited to, all of devices, such as, as well as auser equipment (UE) supporting wideband code division multiple access(WCDMA), LTE, high speed packet access (HSPA), international mobiletelecommunications (IMT)-2020 (5G or new radio), or the like, a mobilestation (MS) supporting the GSM, a user terminal (UT), a subscriberstation (SS), a wireless device, or the like. In addition, the UE may bea portable device such as a smart phone according to a type of usage,and may denote a vehicle, a device including a wireless communicationmodule in the vehicle, or the like, in a V2X communication system. Inaddition, in the case of a machine type communication (MTC) system, theUE may denote a MTC terminal, an M2M terminal, or the like, on which acommunication module enabling machine type communication to be performedis mounted.

In the present disclosure, a base station or a cell generally refers toa station communicating with the UE. The base station or cell is definedas a generic term including, but not limited to, all of various coverageareas, such as a Node-B, an evolved Node-B (eNB), a gNode-B (gNB), a lowpower node (LPN), a sector, a site, various types of antennas, a basetransceiver system (BTS), an access point, a point (e.g., a transmittingpoint, a receiving point, or a transceiving point), a relay node, amegacell, a macrocell, a microcell, a picocell, a femtocell, a remoteradio head (RRH), a radio unit (RU), a small cell, or the like.

The various cells described above is controlled by a base station,therefore the base station may be classified into two categories. 1) Thebase station may be referred to an apparatus that provides a megacell, amacrocell, a microcell, a picocell, a femtocell, and a small cell, inassociation with a radio area, or 2) the base station may be referred toa radio area itself. In case of 1) the base station may be referred toall apparatuses providing any radio area i) by being controlled by thesame entity or ii) by cooperating with one another. A point, atransmission/reception point, a transmission point, a reception point,and the like may be examples of the base station according to methods ofconfiguring the radio area. In case of 2) the base station may be aradio area itself for enabling a UE or a base station for receiving asignal from or transmitting a signal to another UE or a neighboring basestation perspective.

In the present disclosure, the cell may refer to a coverage of a signaltransmitted from a transmission/reception point, a component carrierhaving the coverage of a signal transmitted from a transmission point ora transmission/reception point, or a transmission/reception pointitself.

Uplink (UL) refers to data transmission and reception from a UE to abase station, and downlink (DL) refers to data transmission andreception from a base station to a UE. The DL may denote communicationor a communication path from multiple transmission/reception points to aUE, and the UL may denote communication or a communication path from theUE to the multiple transmission/reception points. At this time, in theDL, a transmitter may be a part of multiple transmission/receptionpoints, and a receiver may be a part of a UE. In the UL, a transmittermay be a part of a UE and a receiver may be a part of multipletransmission/reception points.

The UL and the DL i) transmit/receive control information through one ormore control channels, such as a physical DL control channel (PDCCH), aphysical UL control channel (PUCCH), and the like and ii)transmit/receive data through one or more data channels, such as aphysical DL shared channel (PDSCH), a physical UL shared channel(PUSCH), and the like. Hereinafter, the transmission/reception of asignal through the PUCCH, the PUSCH, the PDCCH, or the PDSCH, may bedescribed as the transmission/reception of the PUCCH, the PUSCH, thePDCCH, or the PDSCH.

Hereinafter, to describe clearly embodiments of the present disclosure,description will be given based on the 3GPP LTE/LTE-A/NR (New RAT)communication systems, but is not limited thereto.

After 4th-generation (4G) communication technology has been developed,studies on 5th-generation (5G) communication technology are in progressin the 3GPP, in order to meet requirements for next generation radioaccess technology under the ITU-R. Specifically, in the 3GPP, studies ona new NR communication technology are in progress independent of 4Gcommunication technology and LTE-A pro having improved LTE-Advancedtechnology according to requirements of the ITU-R to reach 5Gcommunication technology. It is assumed that both the LTE-A pro and theNR will be introduced into 5G communication technology, for convenienceof description, embodiments of the present disclosure will be describedmainly with reference to the NR.

Various operation scenarios of the NR are defined by adding scenariosfor a satellite, a vehicle, a new vertical, and the like, in typical 4GLTE scenarios. In terms of services, the NR supports an enhanced mobilebroadband (eMBB) scenario, a massive machine communication (MMTC)scenario in which i) the density of UEs is high, ii) correspondingdeployment is performed over a wide range, and iii) low data rate andasynchronous access are required, and an Ultra Reliability and LowLatency (URLLC) scenario in which high responsiveness and reliabilityare required and high-speed mobility can be supported.

To satisfy such scenarios, the NR specifies wireless communicationsystems to which at least one of a new waveform and frame structuretechnique, a low latency technique, a millimeter-wave (mmWave) supporttechnique and a forward compatible providing technique is applied. Inparticular, in order to provide forward compatibility, varioustechnological changes in terms of flexibility have been introduced intoNR systems. Main technical features of the present disclosure aredescribed below with reference to the drawings.

<General NR System>

FIG. 1 is a diagram schematically illustrating a structure of a NRsystem.

Referring to FIG. 1, the NR system is divided into a 5G Core Network(5GC) and an NR-RAN part. The NG-RAN includes a gNB and an ng-eNB, whichprovide user plane (SDAP/PDCP/RLC/MAC/PHY) and control plane (RRC)protocol terminations toward a user equipment (UE). Interconnectionbetween gNBs or between the gNB and the ng-eNB is performed through aXNA interface. Each of the gNB and the ng-eNB is connected to the 5GCthrough an NG interface. The 5GC may include an access and mobilitymanagement function (AMF) responsible for a control plane, such as UEaccess, mobility control function, etc., and a user plane function (UPF)responsible for a control function for user data. The NR supports both afrequency range of 6 GHz or lower (FR1, Frequency Range 1) and afrequency range of 6 GHz or higher (FR2, Frequency Range 2).

The gNB denotes a base station providing NR user plane and control planeprotocol terminations toward a UE, and the ng-eNB denotes a base stationproviding E-UTRA user plane and control plane protocol terminationstoward a UE. In the present disclosure, the base station should beunderstood as meaning including both the gNB and the ng-eNB and may beused as meaning of the gNB or the ng-eNB, if necessary.

<NR Waveform, Numerology and Frame Structure>

In the NR, a cyclic prefix (CP)-OFDM waveform using a cyclic prefix isused for downlink transmission, and a CP-OFDM or a Discrete FourierTransform-spread (DFT-s)-OFDM is used for uplink transmission. The OFDMtechnique is considered more attractive technique in combining withmultiple input multiple output (MIMO) and has the advantage capable ofusing a low complexity receiver with high frequency efficiency.

Meanwhile, in the NR, requirements for data rate, latency, coverage,etc. are different for each of the three scenarios described above.Therefore, it is necessary to efficiently satisfy the requirements foreach scenario through frequency bands establishing an NR system. To dothis, a technique has been proposed for efficiently multiplexing aplurality of numerology-based radio resources different from oneanother.

Specifically, NR transmission numerology is determined based on asubcarrier spacing and a cyclic prefix (CP), and the μvalue has anexponential value of 2 based on 15 kHz and exponentially changed, asshown in Table 1 below.

TABLE 1 Subcarrier Supported Supported μ spacing Cyclic prefix for datafor synch 0 15 Normal Yes Yes 1 30 Normal Yes Yes 2 60 Normal, ExtendedYes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR numerology may be classified into fivetypes according to subcarrier spacings. Unlike the NR, in LTE that isone of 4G communication techniques, a subcarrier spacing is fixed with15 kHz. Specifically, in the NR, subcarrier spacings used for datatransmission are 15, 30, 60, and 120 kHz, and subcarrier spacings usedfor synchronous signal transmission are 15, 30, 12, and 240 kHz. Also,an extended CP is applied only to the 60 kHz subcarrier spacing.Meanwhile, as a frame structure of the NR, a frame is defined as alength of 10 ms composed of 10 subframes having the same length of 1 ms.One frame may be divided into 5 ms half frames, and each half frameincludes 5 subframes. In the case of the 15 kHz subcarrier spacing, onesubframe is composed of one slot and each slot is composed of 14 OFDMsymbols. FIG. 2 is a diagram illustrating a frame structure of a NRsystem.

Referring to FIG. 2, the slot is fixedly made up of 14 OFDM symbols inthe case of normal CP, but the length of the slot may vary according tosubcarrier spacings. For example, in the case of a numerology with the15 kHz subcarrier spacing, the slot has 1 ms length identical to thesubframe. In the case of a numerology with the 30 kHz subcarrierspacing, the slot is composed of 14 OFDM symbols and has 0.5 ms length.Therefore, two slots may form one subframe. That is, the subframe andthe frame are defined with a fixed time length, and the slot is definedby the number of symbols. Therefore, the time length may vary accordingto subcarrier spacings.

Meanwhile, NR defines a slot as a basic unit of scheduling and alsointroduces a minislot (or a subslot or a non-slot based schedule) toreduce transmission delay in the radio section. When a wide subcarrierspacing is used, the transmission delay in the radio section may bereduced because the length of one slot is shortened in inverseproportion. The minislot (or subslot) is for efficient support for URLLCscenarios and may be scheduled on the basis of 2, 4, or 7 symbols.

Also, unlike the LTE, the NR defines uplink and downlink resourceallocations on a symbol basis within one slot. In order to reduce HARQlatency, a slot structure capable of directly transmitting HARQ ACK/NACKin a transmission slot is defined, and this slot structure is referredto as a self-contained structure for description.

The NR has been designed to support a total of 256 slot formats, ofwhich 62 slot formats are used in Rel-15. In addition, a common framestructure including an FDD, or a TDD frame is supported through variousslot combinations. For example, the NR supports i) a slot structure inwhich all symbols of a slot are configured in downlink, ii) a slotstructure in which all symbols of a slot are configured in uplink, andiii) a slot structure in which downlink symbols and uplink symbols arecombined. In addition, the NR supports that data transmission isscheduled with data distributed in one or more slots. Accordingly, abase station may inform a UE whether a corresponding slot is a downlinkslot, an uplink slot, or a flexible slot, using a slot format indicator(SFI). The base station may indicate a slot format i) by indicating anindex of a table configured through UE-specific RRC signaling, using theSFI, ii) dynamically through downlink control information (DCI), or iii)statically or quasi-statically through RRC.

<NR Physical Resources>

An antenna port, a resource grid, a resource element, a resource block,a bandwidth part, or the like is considered for a physical resource inthe NR.

The antenna port is defined such that a channel for carrying a symbol onan antenna port may be inferred from a channel for carrying anothersymbol on the same antenna port. If a large-scale property of a channelcarrying a symbol on one antenna port may be inferred from a channelcarrying a symbol on another antenna port, the two antenna ports may bein a quasi co-located or quasi co-location (QC/QCL) relationship. Here,the large-scale property includes at least one of a delay spread, aDoppler spread, a frequency shift, an average received power, and areceived timing.

FIG. 3 is a diagram illustrating a resource grid supported by radioaccess technology.

Referring to FIG. 3, since the NR supports a plurality of numerologiesin the same carrier, a resource grid may be configured according to eachnumerology. In addition, the resource grid may be configured dependingon an antenna port, a subcarrier spacing, and a transmission direction.

A resource block is composed of 12 subcarriers and is defined only inthe frequency domain. In addition, a resource element is composed of oneOFDM symbol and one subcarrier. Therefore, as shown in FIG. 3, the sizeof one resource block may vary according to the subcarrier spacings. Inaddition, the NR defines “Point A” that serves as a common referencepoint for resource block grids, a common resource block, and a virtualresource block.

FIG. 4 is a diagram illustrating a bandwidth part supported by radioaccess technology.

In the NR, the maximum carrier bandwidth is set from 50 MHz to 400 MHzaccording to subcarrier spacings, unlike the LTE in which carrierbandwidth is fixed at 20 MHz. Therefore, it is not assumed that all UEsuse all of these carrier bandwidths. As a result, as shown in FIG. 4, inthe NR, a bandwidth may be configured within a carrier bandwidth part inorder for a UE to use. In addition, the bandwidth part i) is associatedwith one numerology, ii) is composed of a contiguous subset of thecommon resource blocks and iii) can be activated dynamically over time.In the UE, up to four bandwidth parts are configured in each of uplinkand downlink, and data is transmitted/received using an activatedbandwidth part at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidthparts are configured independently. In the case of an unpaired spectrum,the downlink and uplink bandwidth parts are configured in pairs toenable a center frequency to be shared to prevent unnecessary frequencyre-tuning between downlink and uplink operations.

<NR Initial Access>

In the NR, a UE performs cell search and random access procedures toaccess a base station and perform communication.

The cell search is a procedure of i) synchronizing a UE with a cell of acorresponding base station using a synchronization signal block (SSB)transmitted from the base station, ii) acquiring a physical layer cellID, and iii) acquiring system information.

FIG. 5 is a diagram illustrating an exemplary synchronization signalblock in radio access technology.

Referring to FIG. 5, the SSB includes i) a primary synchronizationsignal (PSS) and a secondary synchronization signal (SSS), each of whichoccupies one symbol and 127 subcarriers, and ii) a PBCH configured onthree OFDM symbols and 240 subcarriers.

The UE monitors the SSB in the time and frequency domain and receivesthe SSB.

The SSB may be transmitted up to 64 times for 5 ms. A plurality of SSBsare transmitted in different transmission beams within 5 ms duration,and the UE detects the SSBs, assuming that the SSBs are transmittedevery 20 ms period based on a specific one beam used for transmission.The higher the frequency band is, the greater the number of beams thatmay be used for SSB transmission within 5 ms duration can increase. Forexample, the SSBs may be transmitted using i) up to four different beamsin a frequency band of 3 GHz or lower, ii) up to 8 different beams in afrequency band of 3 to 6 GHz, and iii) up to 64 different beams in afrequency band of 6 GHz or higher.

Two SSBs are included in one slot, and the start symbol and the numberof repetitions in a slot are determined according to subcarrier spacingsas described below.

Meanwhile, the SSB is not transmitted at a center frequency of a carrierbandwidth unlike the SS of the LTE. That is, the SSB may be transmittedon a frequency that is not the center of a system band, and a pluralityof SSBs may be transmitted in the frequency domain in a case wherewideband operation is supported. Thus, the UE monitors a SSB using asynchronization raster, which is a candidate frequency position formonitoring the SSB. A carrier raster and the synchronous raster, whichare center frequency position information of a channel for initialaccess, are newly defined in the NR. The synchronous raster isconfigured with a wider frequency interval than the carrier raster, andthus, may support that a UE rapidly searches the SSB.

The UE may acquire a master information block (MIB) through the PBCH ofthe SSB. The MIB includes minimum information for receiving remainingminimum system information (RMSI) by the UE broadcast from the network.The PBCH may include information on the position of the first DM-RSsymbol in the time domain, information for monitoring SIB1 by the UE(for example, SIB1 numerology information, SIB1 CORESET relatedinformation, search space information, PDCCH related parameterinformation, etc.), offset information between a common resource blockand a SSB (the absolute position of the SSB in a carrier is transmittedvia the SIB1), and the like. Here, the SIB1 numerology information isequally applied to messages 2 and 4 of a random access procedure foraccessing a base station after the UE has completed the cell searchprocedure.

The RMSI means the system information block 1 (SIB1), and the SIB1 isbroadcast periodically (ex, 160 ms) in a corresponding cell. The SIB1includes information necessary for the UE to perform an initial randomaccess procedure, and the SIB1 is periodically transmitted through thePDSCH. In order for the UE to receive the SIB1, the UE is required toreceive numerology information used for SIB1 transmission and controlresource set (CORESET) information used for SIB1 scheduling, through thePBCH. The UE checks scheduling information for the SIB1 using a SI-RNTIin the CORESET, and acquires the SIB1 on the PDSCH according to thescheduling information. Remaining SIB s other than the SIB1 may betransmitted periodically or may be transmitted according to the requestof a UE.

FIG. 6 is a diagram illustrating a random access procedure in radioaccess technology.

Referring to FIG. 6, when cell search is completed, a UE transmits arandom access preamble for random access to a base station. The randomaccess preamble is transmitted through PRACH. Specifically, the randomaccess preamble is transmitted to the base station through PRACH, whichis made up of consecutive radio resources in a specific slot repeatedperiodically. Generally, a contention-based random access procedure isperformed when a UE initially accesses a cell, and a non-contentionbased random access procedure is performed when random access isperformed for beam failure recovery (BFR).

The UE receives a random access response to the transmitted randomaccess preamble. The random access response may include a random accesspreamble identifier (ID), an UL grant (uplink radio resource), atemporary cell-radio network temporary identifier (temporary C-RNTI),and a time alignment command (TAC). Since one random access response mayinclude random access response information for one or more UEs, therandom access preamble identifier may be included to inform which UE theincluded UL grant, temporary C-RNTI and TAC are valid to. The randomaccess preamble identifier may be an identifier of a random accesspreamble received by the base station. The TAC may be included asinformation for adjusting uplink synchronization by a UE. The randomaccess response may be indicated by a random access identifier on thePDCCH, i.e., a random access-radio network temporary identifier(RA-RNTI).

When receiving the valid random access response, the UE processesinformation included in the random access response and performsscheduled transmission to the base station. For example, the UE appliesthe TAC and stores the temporary C-RNTI. In addition, using the ULgrant, the UE transmits data stored in a buffer or newly generated datato the base station. In this case, information for identifying the UEshould be included.

The UE receives a downlink message for contention resolution.

<NR CORESET>

A downlink control channel in the NR is transmitted on a controlresource set (CORESET) having a length of 1 to 3 symbols and transmitsup/down scheduling information, slot format index (SFI) information,transmit power control information, and the like.

Thus, in the NR, in order to secure the flexibility of the system, theCORESET is introduced. The control resource set (CORESET) refers to atime-frequency resource for a downlink control signal. The UE may decodea control channel candidate using one or more search spaces in a CORESETtime-frequency resource. Quasi CoLocation (QCL) assumption isestablished for each CORESET, which is used for the purpose of informingcharacteristics for analogue beam directions besides characteristicsassumed by typical QCL, such as delayed spread, Doppler spread, Dopplershift, or average delay.

FIG. 7 is a diagram illustrating CORESETs.

Referring to FIG. 7, a CORESET may be configured in various forms withina carrier bandwidth in one slot. The CORESET may include a maximum of 3OFDM symbols in the time domain. In addition, the CORESET is defined asa multiple of six resource blocks up to the carrier bandwidth in thefrequency domain.

The first CORESET is indicated through the MIB as a part of an initialbandwidth part configuration to enable additional configurationinformation and system information to be received from the network.After establishing a connection with a base station, a UE may receiveand configure one or more pieces of CORESET information through RRCsignaling.

Hereinafter, the URLLC will be described.

Hereinafter, the URLLC service will be described in detail.

The URLLC service is devised to meet requirements of the UE forscenarios in which reliability of data transmission and latencyminimization are more important than data transmission rate, and bothLTE system and the NR will support the URLLC.

Examples of the scenarios in which the reliability of data transmissionand the latency minimization are important include a scenario for anautonomous vehicle required to recognize changes rapidly in an externalsituation such as an accident, a scenario for warning the detection ofdangerous material leakage within a limited time, or the like.

As an example of the requirements related to the latency of the URLLCservice, end-to-end (E2E) latency is required to be within 5 ms, and thelatency of the user plane is required to be within 0.5 ms. As an exampleof the requirements related to the transmission reliability of the URLLCservice, a block error rate (BLER) is required to be 10-5 or less, andit is required to support mobility for a UE moving at a high speed up to500 km.

In order to satisfy the requirements for the URLLC service in the nextgeneration mobile communication system, it is necessary for a resourceused for data transmission/reception to be allocated rapidly to a UEusing the URLLC service. In addition, it is necessary for a resource tobe allocated to a UE using the URLLC service with a higher priority thana UE using an eMBB service or an mMTC service.

<NR Mini-Slot>

As described above, in the NR, one subframe is determined to be 1 msregardless of the subcarrier spacing (SCS). One slot is composed of 14OFDM symbols, and the number of slots forming one subframe may bedifferent according to subcarrier spacings.

Thus, considering that it varies depending on the subcarrier spacings,in the NR, resources for data transmission/reception may be normallyscheduled on a per-slot basis. This scheduling scheme is referred to asslot-based scheduling.

However, it is necessary for a UE using the URLLC service to beallocated resources for data transmission/reception in a unit smallerthan the slot in order to satisfy a corresponding low latencyrequirement. Thus, with a subslot smaller than the slot defined, atechnique for scheduling resources on a per-subslot basis is introducedinto the NR, and this scheduling scheme is referred to as non-slot basedscheduling.

The subslot may also be referred to as a mini-slot and may composed of2, 4, or 7 OFDM symbols, unlike the slot composed of 14 OFDM symbols.Accordingly, when resources are scheduled on a per-subslot basis, a UEusing the URLLC service may be allocated resources for datatransmission/reception more rapidly.

FIG. 8 is a diagram illustrating a comparison between a subslot and aslot.

Referring to FIG. 8, one slot is composed of 14 OFDM symbols, whereas asubslot (mini-slot) is composed of 2 or 4 OFDM symbols. That is, whenresources are scheduled on a per-subslot basis, a plurality of UEs maybe allocated resources within one slot and then use them for datatransmission/reception.

<Preemption>

Meanwhile, in order for a UE using the URLLC service to be allocated aresource with a high priority, the next generation mobile communicationsystem provides a preemption technique that allows the UE to use aresource already allocated to another UE using the eMBB service or themMTC service.

As described above, in order to support the URLLC service, it isnecessary to subdivide a unit for performing resource scheduling in thetime domain. As a result, a resource may be allocated to a UE using theURLLC service on the basis of a subslot, which is a time unit smallerthan a slot.

On the contrary, it is preferable to define a unit for performingresource scheduling for a UE using the eMBB service or the mMTC serviceon the basis of a longer time compared with a UE using the URLLCservice. The longer scheduling time unit, the less overhead that occursin the process of controlling scheduling.

However, in the case of scheduling on the basis of such a long time, itis necessary to consider a case where a UE using the URLLC service isurgently required to be allocated a resource for data transmission whilea UE using the MMTC service or the eMBB service allocated a resource onthe basis of a long time is using the resource. For example, URLLCtraffic may occur during eMBB transmission.

In this case, if a UE using the URLLC service is allocated a resourceafter UEs using the eMBB service or the mMTC service have used allallocated resources, there is a possibility of not satisfying thelatency requirement required by the URLLC service.

As one way to solve this problem, it is possible to consider a method ofconfiguring scheduling in the time domain on a short time basis for thee-MBB service and the mMTC service as well as the URLLC service.However, configuring scheduling in the time domain on a short time basisfor all services for URLLC service traffic that is intermittentlyoccurring results in increasing scheduling overhead as described above.

Therefore, in a case where a UE using the URLLC service required tosatisfy latency requirements is urgently required to be allocated aresource, instead of being allocated a resource with scheduling on thebasis of time units different from one another in the time domain foreach service, it is possible for the UE using the URLLC service topreempt and use a part of a resource(s) allocated to a UE using the eMBBservice or the mMTC service.

In a case where the UE using the URLLC service has preempted theresource, when a UE that has been originally allocated the resourcereceives information indicating that the preemption has occurred, the UEis required not to use the resource any longer or discard datatransmitted through the resource.

That is, when a UE using the eMBB service or the mMTC service isinstructed that an allocated resource is preempted by another UE usingthe URLLC service, the UE using the eMBB service or the mMTC service isrequired to flush data for the corresponding preempted resource areafrom the soft buffer.

FIG. 9 is a diagram illustrating that a UE using a RLLC service preemptsa resource allocated to a UE using an eMBB service.

Referring to FIG. 9, a diagram (a) illustrates a case where a preemptionoccurs when a numerology applied to the URLLC service and a numerologyapplied to the eMBB service are different from each other.

In the diagram (a) of FIG. 9, a UE using the URLLC service selects anduses a 4th OFDM symbol from the left in the time domain among resourcesallocated to a UE using the eMBB service, a 4th to 7th subcarrierresources from the bottom in the frequency domain.

In this case, since the numerology for the URLLC service is applied toresources preempted by the UE using the URLLC service, an OFDM symbollength and a subcarrier spacing of the preempted resources are differentfrom a symbol length and a subcarrier spacing of resources allocated tothe UE using the eMBB service.

A diagram (b) of FIG. 9 illustrates a case where preemption occurs whena numerology applied to the URLLC service and a numerology applied tothe eMBB service are the same.

Similar to the diagram (a) of FIG. 9, in the diagram (b) of FIG. 9, a UEusing the URLLC service preempts and uses a 4th OFDM symbol from theleft in the time domain among resources allocated to a UE using the eMBBservice, a 4th to 7th subcarrier resources from the bottom in thefrequency domain.

In this case, since the same numerology is applied to the resourcespreempted by the UE using the URLLC service, an OFDM symbol length and asubcarrier spacing of the preempted resources are identical to a symbollength and a subcarrier spacing of resources allocated to the UE usingthe eMBB service.

<URLLC HARQ>

The NR supports flexible HARQ timing based on dynamic downlink controlinformation considering dynamic TDD operation. For example, in a statewhere a plurality of PDCCH-to-PDSCH and PDSCH-to-PUCCH time delay valuesare set for each UE through RRC signaling, a specific delay value isindicated using downlink or uplink scheduling information.

Meanwhile, in order to reduce latency in the URLLC service, it isnecessary to configure a retransmission unit smaller than the LTE.

In the case of the LTE, when transmitting data, it is determined whetherdata retransmission is performed on a transmission block (or a transportblock) (TB) basis.

Specifically, when a transmitting end transmits a transmission block, a24-bit CRC (Cyclic Redundancy Check) is additionally inserted into theentire transmission block, and the CRC is additionally inserted intoeach code block (CB) composing the transmission block.

A receiving end that receives the transmission block transmitted fromthe transmitting end performs a CRC check on the CRC for the entiretransmission block and the CRC for each code block.

At this time, if the CRC check is successful for both the CRC for theentire transmission block and the CRC for each code block, the receivingend determines that there is no error in the corresponding transmissionblock. On the other hand, if the CRC check fails for either the CRC forthe entire transmission block or the CRC for each code block, thereceiving end determines that there is an error in the correspondingtransmission block and requests retransmission for the entiretransmission block.

However, if it is requested to retransmit the entire transmission blockeven though an error has occurred in only a part of a transmissionblock, there occurs a problem that a resource used for retransmittingthe transmission block increases.

Therefore, in the NR, when there is an error in a part of a transmissionblock, it is defined to perform retransmission only for the part inwhich the error has occurred, and thereby to provide a function forreducing resources required for the retransmission of the transmissionblock. In this case, the retransmission is performed on the basis of nota transmission block but a code block group (CBG) smaller than thetransmission block. Therefore, such a retransmission method is referredto as CBG based retransmission.

In the CBG based retransmission, one or more code blocks may be groupedinto one code block group. Thus, a transmission block may be composed ofone or more code block groups.

When determining whether retransmission is required for a transmissionblock, a receiving end checks a CRC of each code block composing thecode block group to inspect whether an error has occurred. If an erroroccurs in any of code blocks composing the code block group, thereceiving end requests retransmission of the code block group.

If one transmission block is composed of N code block groups, thereceiving end records information indicating which code block groupshould be retransmitted among the N code block groups, in HARQ ACK/NACKfor the corresponding transmission block. The transmitting end mayretransmit only the corresponding code block group indicated forretransmission by receiving the corresponding HARQ ACK/NACK.

FIG. 10 is a diagram illustrating a transmission block configuration forsupporting code block group based retransmission.

Referring to FIG. 10, the entire transmission block is composed of atotal of 8 code blocks from CB #0 to CB #7. In this case, i) code blocksCB #0 and CB #1 form a code block group CBG #0, ii) code blocks CB #2and CB #3 form a code block group CBG #1, iii) code blocks CB #4 and CB#5 form a code block group CBG #2, and iv) code blocks CB #6 and CB #7form code block group CBG #3.

If a CRC error occurs in the code block CB #2 or the code block CB #3 ina transmission block received by a receiving end, when transmitting HARQACK/NACK information to a transmitting end, the receiving end configuresi) ACK for the code block group CBG #0, ii) NACK for the code blockgroup CBG #1, iii) ACK for the code block group CBG #2, and iv) ACK forthe code block group CBG #3, and transmits the configured information.

When receiving the HARQ ACK/NACK information and identifying that NACKis set to only the code block group CBG #1, the transmitting end mayperform retransmission only for the corresponding code block group CBG#1 to the receiving end.

Information on which code block group is retransmitted among code blockgroups forming a transmission block is indicated through downlinkcontrol information (DCI). It is indicated whether or not a specificcode block group is retransmitted through a code block grouptransmission indicator (CBGTI, CBG Transmit Indicator) of the downlinkcontrol information. It is also indicated whether or not soft combiningis to be performed for a retransmitted code block group through a codeblock group flush indicator (CBGTI, CBG Flush Indicator) of the downlinkcontrol information.

A frequency, a frame, a subframe, a resource, a resource block (RB), aregion, a band, a sub-band, a control channel, a data channel, asynchronization signal, various reference signals, various signals, andvarious messages associated with NR of the present disclosure may beinterpreted as being used in the past or present or as various meaningsto be used in the future.

Summary of NR(New Radio)

Recently, the 3rd generation partnership project (3GPP) has approved the“Study on New Radio Access Technology”, which is a study item forresearch on next-generation/5G radio access technology. On the basis ofthe Study on New Radio Access Technology, Radio Access Network WorkingGroup 1 (RAN WG1) has been discussing frame structures, channel codingand modulation, waveforms, multiple access methods, and the like for thenew radio (NR).

The NR is required to be designed not only to provide an improved datatransmission rate as compared with the long term evolution(LTE)/LTE-Advanced, but also to meet various requirements of eachdetailed and specific usage scenario. In particular, an enhanced mobilebroadband (eMBB), massive machine-type communication (mMTC), and ultrareliable and low latency communication (URLLC) are proposed asrepresentative usage scenarios of the NR. In order to meet therequirements of the individual scenarios, it is required to design framestructures to be flexible, compared with the LTE/LTE-Advanced.

Specifically, the eMBB, mMTC, URLLC are considered as representativeusage scenarios of the NR having been discussed in the 3GPP. Since eachusage scenario imposes a different requirement of data rate, latency,coverage, etc., discussions on necessity for techniques of efficientlymultiplexing radio resource units based on different types of numerology(e.g., a subcarrier spacing (SCS), a subframe, a transmission timeinterval (TTI), etc.) are in progress as methods for efficientlysatisfying requirements of each usage scenario through a frequency bandconfiguring an NR system.

To this end, there have been discussions on i) methods of multiplexingnumerologies having subcarrier spacing (SCS) values different from oneanother based on TDM, FDM or TDM/FDM through one NR carrier, and ii)methods of supporting one or more time units in configuring a schedulingunit in the time domain.

In this regard, the NR has defined i) a subframe as one type of a timedomain structure, and as a reference numerology to define acorresponding subframe duration, ii) a single subframe duration composedof 14 OFDM symbols of normal CP overhead based on a subcarrier spacing(SCS) of 15 kHz, which is the same as the LTE. Therefore, the subframein the NR has the time duration of 1 ms. Unlike the LTE, since thesubframe in the NR is an absolute reference time duration, a slot and aminislot may be defined as a time unit for actual UL/DL data scheduling.In this case, the number of OFDM symbols included in the slot, a yvalue, has been determined to be equals to 14 regardless ofnumerologies, but not limited thereto.

Therefore, a slot may be composed of 14 symbols. In accordance with atransmission direction for a corresponding slot, all symbols may be usedfor DL transmission or UL transmission, or the symbols may be used inthe configuration of a DL portion+a gap+a UL portion.

Further, a minislot composed of fewer symbols than the slot has beendefined in a numerology (or SCS), and as a result, a short time domainscheduling interval may be configured for UL/DL data transmission orreception based on the minislot. Also, a long time domain schedulinginterval may be configured for the UL/DL data transmission or receptionby slot aggregation.

In particular, in the case of transmission/reception of latency-criticaldata, such as the URLLC, it may be difficult to meet latencyrequirements when scheduling is performed on the basis of a slot having0.5 ms (7 symbols) or 1 ms (14 symbols) defined in a frame structurebased on a numerology having a small SCS value such as 15 kHz. To solvethis problem, by defining a minislot composed of fewer OFDM symbols thanthe slot, it is possible to enable scheduling for latency-critical data,such as the URLLC, to be performed based on the minislot.

Further, methods have been discussed for scheduling data according tolatency requirements based on a slot (or a minislot) length defined foreach numerology, by multiplexing numerologies having different SCSvalues from one another in one NR carrier, using the TDM or FDMtechnique, as described above. For example, as shown in FIG. 2, since asymbol length for the SCS of 60 kHz is reduced by about a fourth of thatfor the SCS of 15 kHz, when one slot is composed of seven OFDM symbolsin both the cases, a slot length based on the SCS of 15 kHz is 0.5 ms,whereas a slot length based on the SCS of 60 kHz reduces to about 0.125ms.

As described above, discussion on methods of satisfying each requirementof URLLC and eMBB is in progress by defining different SCSs or differentTTI lengths in the NR.

NR PDCCH

Physical layer control information, such as DL allocation downlinkcontrol information (DCI) and UL grant DCI is transmitted and receivedthrough the PDCCH, in the NR and LTE/LTE-A systems. A control channelelement (CCE) is defined as a resource unit for transmission of thePDCCH. In the NR, a CORESET (Control Resource Set), which is afrequency/time resource for PDCCH transmission, may be configured foreach UE, with reference to FIG. 7, as described above. In addition, eachCORESET may be composed of one or more search spaces configured by oneor more PDCCH candidates for monitoring the PDCCH by a UE.

Wider Bandwidth Operations

A typical LTE system supports scalable bandwidth operations for an LTEcomponent carrier (CC). An LTE service provider may organize a bandwidthof at least 1.4 MHz up to 20 MHz according to a frequency deploymentscenario when configuring one LTE CC. Accordingly, any normal LTE UEsupports transmission/reception capabilities of the bandwidth of 20 MHzfor one LTE CC.

However, the NR is designed for enabling UEs havingtransmission/reception bandwidth capabilities different from one anotherto be supported in one broadband NR component carrier. Accordingly, asillustrated in FIG. 4, it is required to i) configure one or morebandwidth parts (BWPs) composed of subdivided bandwidths for an NRcomponent carrier (CC), and ii) support flexible wider bandwidthoperations by configuring and activating BWPs different from one anotherfor each UE.

Specifically, in the NR, one or more BWPs may be configured through oneserving cell configured from a UE perspective. The corresponding UE maytransmit/receive UP/DL data by activating one DL BWP and one UP BWP inthe serving cell. In addition, in a case where a plurality of servingcells are established on a UE, that is, carrier aggregation (CA) isapplied to the UE, it is possible to activate one DL bandwidth partand/or one UL BWP for each serving cell, and then transmit and/orreceive UP/DL data using a radio resource of each serving cell.

Specifically, an initial bandwidth part may be defined for an initialaccess procedure in a serving cell, and one or more UE-specific BWPs maybe configured through RRC signaling dedicated for each UE, and a defaultbandwidth part may be defined for a fallback operation for each UE.

In this case, it may be defined to activate and use a plurality ofdownlink and/or uplink BWPs simultaneously according to theconfigurations of BWPs and capabilities of a UE in any serving cell. Inthis regard, NR rel-15 defines to activate and use only one DL BWP andone UL BWP in any UE at any time.

NR MCS & TBS Determination

In the typical LTE system, a base station transmits modulation andcoding scheme (MCS) indication information for PDSCH or PUSCHtransmission/reception to a UE through downlink control information(DCI). Also, based on an MCS table or a TBS table, a modulation orderand a transport block size (TBS) index are mapped according to the MCSindication information, i.e., MCS index information, indicated throughthe DCI, and a TBS is mapped based on the TBS index and the number ofallocated TBSs. Details of methods of configuring an MCS and a relevantTBS can be found in the documents of 3GPP TS 36.213 and TS 38.214.

Also, methods of determining the MCS and the TBS of the LTE may beapplied equally in the NR.

In the present disclosure, a method and apparatus are proposed forconfiguring the MCS and the TBS to support data transmission withdifferent target BLERs in NR or LTE/LTE-A systems.

As a usage scenario provided by the NR and the LTE/LTE-A systems, thereis increasing importance of methods for effectively supporting, as wellas data related to the eMBB service to maximize data transmission rate,data related to the URLLC service to maximize reliability.

In particular, since the URLLC requires an improved target BLER (BlockError Rate) compared with a target BLER for typical eMBB data,therefore, it is required to design a new MCS table or TBS table isrequired for this purpose.

In this present disclosure, a method and apparatus are proposed forefficiently operating a MCS table or a TBS table based on differenttarget BLERs if the MCS table or the TBS table is defined as describedabove.

As described above, there occurs a difference between reliabilityrequirements required for data transmission according to usagescenarios, and accordingly, target BLERs for data transmission, i.e.PDSCH transmission or PUSCH transmission, may be different. To satisfysuch separate target BLERs, it is required to define i) a separate CQItable for CQI reporting of a UE for each target BLER, and ii) a separateMCS table for each target BLER.

For example, in the case of an MCS table optimized for maximizing thetransmission rate, such as in the eMBB, it is possible to configure anMCS table based on higher order modulation. For example, in the case ofan MCS table for reliability-critical data, such as in the URLLC, it ispossible to configure an MCS table based on lower order modulation. Thatis, according to the target BLER values, as the target BLER is higher,it is possible to configure an MCS table having an MCS index based on ahigher order modulation scheme such as 64QAM, 256QAM, or 1024QAM. As thetarget BLER is lower, it is possible to configure another MCS tablehaving an MCS index based on a lower order modulation scheme such asQPSK or 16 QAM may be constructed.

Accordingly, in the NR or the LTE/LTE-A systems, a separate CQI tablefor CQI or CSI reporting of a UE may be defined for each target BLER.That is, it is possible to define a plurality of CQI tables.Accordingly, i) a base station or a network may configure configurationinformation on a CQI table to be applied for CQI reporting in a UE basedon a target BLER required for each UE through higher layer signaling,and ii) MCS table configuration may be performed according to theconfigured CQI table information.

That is, a plurality of different CQI tables may be defined according totarget BLERs for data transmission/reception. CQI table configurationinformation to be applied for CQI reporting for each UE may beconfigured by the base station and transmitted to each UE through higherlayer signaling. For example, CQI table A, CQI table B, CQI table C, . .. etc. may be defined for each target BLER, and a CQI table to beapplied to each UE may be configured. Further, it is possible to definea plurality of different MCS tables or TBS tables for datatransmission/reception through the PDSCH/PUSCH for each target BLER orfor each relevant CQI table.

That is, MCS table A, MCS table B, MCS table C, . . . , etc. may bedefined for each target BLER or for each relevant CQI table. An MCStable to be applied for data channel transmission/reception for each UEmay be defined to be determined according to CQI table configurationinformation. As another example, MCS table A, MCS table B, MCS table C,. . . , etc. may be defined for each target BLER or for each relevantCQI table. A TBS table to be applied for data channeltransmission/reception for each UE may be defined to be determinedaccording to the CQI table configuration information.

As another method of configuring the CQI table and the relevant MCStable or TBS table, a method may be defined for selecting a dynamic MCStable or TBS table. For example, it is possible to configuresimultaneously both a session (i.e., an eMBB-based service) thatrequires a high data transmission rate and a session (i.e., a URLLCservice) that requires high reliability, for any one UE. Accordingly, itmay be necessary for one UE to simultaneously support data transmissionbased on different target BLERs.

In this case, as described above, it is required to configure a dynamicMCS table or TBS table for each PDSCH or PUSCH transmission other than amethod of configuring a semi-static MCS table or TBS table throughhigher layer signaling.

In this case, a plurality of CQI reporting or CSI reporting processesmay be established in a base station or a network for any one UE. Aseparate CQI table to be applied for CQI reporting is configured foreach CQI reporting or CSI reporting process, and then information on theconfigured separate CQI table may be transmitted to a corresponding UEthrough higher layer signaling.

In addition, when the eMBB-based service and the URLLC-based service aresimultaneously supported for any one UE, target BLERs may be differentfor each PDSCH or PUSCH transmission for the corresponding UE, asdescribed above. Accordingly, it is necessary to define a method ofdynamically configuring an MCS table to be applied for each PDSCH orPUSCH transmission.

As a method for this, a base station may be defined to dynamicallyconfigure information for selecting an MCS table to be applied throughscheduling DCI on the PDSCH or PUSCH and then signals to a correspondingUE. That is, in configuring a DL allocation DCI format or a UL grant DCIformat for a UE, it may be defined to include an information area or aninformation field for selecting the MCS table.

As another method for selecting the MCS table through scheduling DCI onthe PDSCH or the PUSCH, corresponding information may be implicitlysignaled through the scheduling DCI.

For example, the MCS table selection information may be implicitlydetermined by a RNTI for PDCCH decoding of a UE. That is, when such anew MCS table for the URLLC is configured for a UE, the base station mayallocate a new RNTI for the new MCS table through higher layersignaling. For example, an MCS-C-RNTI may be allocated for applying thenew MCS table for the URLLC. The UE may derive corresponding MCS tableselection information based on the MCS-C-RNTI, which is the new RNTI.The MCS-C-RNTI is scrambled by a CRC of the PDCCH.

Specifically, in addition to scheduling control information based on aMCS table defined for providing the typical eMBB service, i.e., theC-RNTI or the CS-RNTI allocated for UE-specific DL allocation DCI or ULgrant DCI transmission/reception, it is possible to define i) separatelyscheduling control information based on an MCS table newly defined forthe URLLC, i.e., the MCS-C-RNTI or the MCS-CS-RNTI for UE-specific DLallocation DCI or UL grant transmission/reception, and ii) an MCS tableto be selected based on this.

The new MCS-C-RNTI or MCS-CS-RNTI for the URLLC is either explicitlyallocated by the base station through higher layer signaling or definedas a function of the typical C-RNTI or CS-RNTI allocated for the UE. Forexample, a value obtained by adding a specific value to the allocatedC-RNTI or CS-RNTI may be defined as an MCS-C-RNTI or MCS-CS-RNTI valuefor DCI transmission/reception based on the MCS table defined for theURLLC.

Whether an information area for selecting an MCS table is included inthe DL allocation DCI format or the UL grant DCI format configured formonitoring by a UE may be i) configured through higher layer signalingfor each UE, or ii) implicitly determined depending on whether aplurality of CQI reports or CSI reports based on different CQI tablesfor each target BLER is configured.

That is, when a plurality of CQI reports or CSI reports based on CQItables different from one another are configured, the DL allocation DCIformat or the UL grant DCI format for a corresponding UE may be definedto include an information area for selecting an MCS table. Otherwise,the DL allocation DCI format or the UL grant DCI format for thecorresponding UE may be defined not to include the information area forselecting an MCS table.

In addition, the size of the information area for selecting an MCS tableis determined i) by the maximum number of MCS tables, an N vale (eg, log2N bits), for each target BLER defined in the NR system or the LTE/LTE-Asystem, or ii) by the number of the CQI tables, a M value (Eg, log 2Mbits), applied by CQI or CSI reporting processes established for acorresponding UE, and the M value.

As another method for configuring the MCS table, it may be defined toconfigure an MCS table to be applied for each CORESET or search spaceconfigured for a UE. For example, when a CORESET is configured for a UE,it is possible to define that a base station i) configures MCSinformation included in the PDCCH transmitted through the CORESET, morespecifically DL allocation DCI or UL grant DCI, ii) configures an MCStable for interpreting the MCS information, and iii) transmits it to thecorresponding UE through higher layer signaling.

For example, when CORESET A, CORESET B, and CORESET C are configured fora UE, and support for MCS table A and MCS table B according to targetBLER A and target BLER B for data transmission required by the UE isrequired, it is possible to define that the base station configures MCSconfiguration information included in the DL allocation DCI or the ULgrant DCI for each CORESET and transmits MCS table configurationinformation used for determining by the UE which one of the MCS table Aand the MCS table B is applied through higher layer signaling.

That is, when configuration or reconfiguration information for eachCORESET A, CORESET B, and CORESET C is transmitted, it is possible todefine that the configuration or reconfiguration information includesMCS table configuration information to be applied to the DL allocationDCI or the UL grant DCI transmitted through a corresponding CORESET.

As another example, the MCS table to be applied may be configured foreach search space configured in a CORESET or through a plurality ofCORESETs. For example, a base station may configure the MCS table to beapplied for each search space and transmit to a US through higher layersignaling.

As another example, the MCS table may be implicitly configured by eachsearch space kind/type (e.g., CSS or UE-specific SS) or an aggregationlevel (AL) of PDCCH candidates composing each search space.

As another example, the search space may be defined as a set of CCEscomposed of PDCCH candidates based on an aggregation level (AL).Accordingly, the MCS table is configured for each search space, whichmay be construed in the same meaning as the MCS table is configured foreach set of PDCCH candidates composed for each aggregation level (AL).

As another method for configuring the MCS table, an MCS table may bedefined to be implicitly applied is determined according to atransmission method of the PDCCH. For example, the MCS table to beapplied may be determined according to i) whether interleaving isapplied, or PDCCH is repeatedly transmitted, or ii) a bundle size.

As another method for configuring the MCS table to be applied, an MCStable to be applied may be configured for each DCI format configured tomonitor by a UE. Specifically, a DL allocation DCI format or UL grantDCI format and an MCS table to be applied may be separately defined, foreach target BLER.

For example, when data transmission/reception based on target BLER A andtarget BLER B is supported in an NR system or LTE/LTE-A system, it ispossible to define an MCS table for the target BLER A, and one or moreDL allocation or UL grant DCI formats based on this. In addition, an MCStable for the target BLER B and one or more DL allocation or UL GrantDCI formats may be defined separately from each other. Accordingly, theMCS table to be applied may be defined to be implicitly mapped accordingto the DCI format configured for monitoring by a UE through a CORESET orsearch space.

As another example, when a DCI format for monitoring by each UE isconfigured or a PDSCH/PUSCH transmission mode is set, it is possible todefine that the MCS table configuration information to be applied, whichis included in data or information to be transmitted by theconfiguration or the setting, is explicitly transmitted to the UEthrough higher layer signaling.

In this case, the higher layer signaling includes MAC CE signaling orRRC signaling and may be cell-specific or UE-specific higher layersignaling.

In the present disclosure, methods are proposed for configuring an MCStable for PDSCH/PUSCH transmission for a UE when different MCS tablesare defined for each target BLER, and embodiments of the presentdisclosure may be applied regardless of a specific method forconfiguring an MCS table for each target BLER.

In configuring a plurality of MCS tables described above, when aplurality of TBS tables are defined for each target BLER, TBS tableconfiguration and selection methods may be applied in the same manner asthe MCS table configuration and selection methods.

In addition, in a case where a plurality of CQI or MCS tables aredefined for each target BLER for data transmission in the NR orLTE/LTE-A systems, as described above, it is possible to define adefault (or fallback) CQI table or MCS table for each UE. The defaultMCS table may be defined as an MCS table to be applied in fallbackoperation of a corresponding UE.

For example, in the case of a UE-specific DCI (e.g., DL allocation DCIor UL grant DCI) transmitted through a common search space (CSS) or afallback DCI format, a base station may configure an MCS index based ona default MCS table defined for a corresponding UE, and then cause theUE to construe it, regardless of the MCS table configuration method andthe resultant UE-specific MCS table configuration information. Thedefault MCS table may be defined in such a manner that i) a specific MCStable for each system/network may be fixed as a default MCS table forall UEs based on the corresponding system/network, ii) each separate MCStable according to capabilities of UEs, etc. may be defined as a defaultMCS table, or iii) a default MCS table may be configured by thecorresponding network through cell-specific higher layer signaling orUE-specific higher layer signaling.

In addition, one or more cases/embodiments where a MCS table is selectedfrom any or all combinations of the above-described methods may beincluded in the scope of the present disclosure.

As described above, in a case where an MCS table or a TBS table based ondifferent target BLERs is defined, a method and apparatus have beendescribed for efficiently operating the MCS table or the TB S table.Hereinafter, referring to FIGS. 10 to 13, methods and apparatuses willbe described for transmitting/receiving control information for aphysical data channel, such as a PDSCH or a PUSCH through a physicaldownlink control channel and transmitting/receiving a physical datachannel. Although the methods and apparatuses will be described usingsome of the embodiments described above, they are equally applicable toother embodiments.

FIG. 11 is a flow chart illustrating a method of a base station fortransmitting control information on a physical uplink shared channelaccording to an embodiment of the present disclosure.

Referring to FIG. 11, a method of a base station is provided fortransmitting control information on a physical uplink data channel(physical uplink shared channel). The method 1100 includes transmittingcontrol information indicating a specific modulation and coding scheme(MCS) index corresponding to modulation and coding scheme (MCS)information to be applied to the physical uplink shared channel througha physical downlink control channel (S1110), and receiving the physicaluplink shared channel modulated based on specific MCS informationdetermined using the specific MCS index and one of two or more MCStables containing modulation order information corresponding to thespecific MCS index (S1120). These MCS tables may additionally include atarget code rate corresponding to the specific MCS index, which iscalculated by the target BLER described above and spectral efficiency.

In the transmitting S1110, a UL grant DCI format for a UE may include aninformation region or an information field indicating the specificmodulation and coding scheme (MCS) index corresponding to the specificmodulation and coding scheme (MCS) information. This information fieldmay be an MCS index field.

At least one of the two or more MCS tables may be an MCS table based ona higher modulation order including 64QAM or 256QAM, and another of theMCS tables may be an MCS table based on a lower modulation orderincluding QPSK or 16QAM.

For example, in the case of an MCS table optimized for maximizing thetransmission rate, such as the eMBB, an MCS table may be configuredbased on higher order modulation. For example, in the case of an MCStable for reliability-critical data, such as in the URLLC, an MCS tablemay be configured based on lower order modulation. That is, according tothe target BLER values, as a corresponding target BLER is higher, an MCStable having an MCS index may be configured based on a higher ordermodulation scheme such as 64QAM, 256QAM, or 1024QAM. As a target BLER islower, another MCS table having an MCS index may be configured based ona lower order modulation scheme such as QPSK or 16 QAM.

The base station may implicitly signal information for selecting one ofthe two or more MCS tables through UL grant DCI for the PUSCH.

One of the two or more MCS tables may be determined by an RNTI valuescrambled with a CRC of the physical downlink control channel (PDCCH).The RNTI may be a new MCS-C-RNTI or a new MCS-CS-RNTI that isadditionally allocated for the URLLC other than a typical C-RNTI and atypical CS-RNTI.

For example, the information for selecting one of two or more MCS tablesmay be implicitly determined by a RNTI for PDCCH decoding of the UE.That is, when such a new MCS table for the URLLC is configured for anyUE, a new RNTI for the new MCS table, i.e., an MCS-C-RNTI or anMCS-CS-RNTI may be allocated by the base station through higher layersignaling. The UE may derive information for selecting one of two ormore MCS tables based on the new RNTI, i.e., the MCS-C-RNTI or theMCS-CS-RNTI.

Specifically, in addition to scheduling control information based on anMCS table defined for providing the typical eMBB service, i.e., theC-RNTI or the CS-RNTI allocated for UE-specific DL allocation DCI or ULgrant DCI transmission/reception, i) scheduling control information maybe separately defined based on an MCS table newly defined for the URLLC,i.e., the new RNTI (e.g., the MCS-C-RNTI or the MCS-CS-RNTI) forUE-specific DL allocation DCI or UL grant transmission/reception, andii) one of two or more MCS tables may be selected based on this newlydefined information.

As another method of selecting one of two or more MCS tables, an MCStable to be applied may be selected for each search space configured forany UE.

One of the two or more MCS tables may be determined by a type of searchspace through which physical downlink control channel (PDCCH)transmission is performed. The type of search space may be a UE-specificsearch space.

That is, the MCS table may be implicitly configured by each search spacekind/type (e.g., CS or UE-specific SS) through which the physicaldownlink control channel (PDCCH) transmission is performed.

In the receiving S1120, the base station receives the physical uplinkshard channel (PUSCH) modulated based on the specific MCS informationdetermined using the specific MCS index and one of the two or more MCStables.

That is, the UE determines the specific MCS information using thespecific MCS index and one of two or more MCS tables. The UE encodes thephysical uplink shard channel (PUSCH) based on the specific MCSinformation.

The UE transmits this physical uplink shared channel (PUSCH) to the basestation. The base station receives this physical uplink shared channel(PUSCH) from the UE.

FIG. 12 is a flowchart illustrating a method of a UE for receivingcontrol information on a physical data channel according to anembodiment of the present disclosure.

Referring to FIG. 12, a method of a UE is provided for receiving controlinformation on a physical data channel. The method 1200 includesreceiving control information indicating a specific modulation andcoding scheme (MCS) index corresponding to modulation and coding scheme(MCS) information on a physical data channel through a physical downlinkcontrol channel (S1210), and determining specific MCS information usedfor the physical data channel using the specific MCS index and one oftwo or more MCS tables containing modulation order informationcorresponding to the specific MCS index (S1220). These MCS tables mayadditionally include a target code rate corresponding to the specificMCS index, which is calculated by the target BLER described above andspectral efficiency.

The physical data channel may be a physical downlink data/shard channel(PDSCH) or a physical uplink data/shard channel (PUSCH).

In the receiving S1210, a DL allocation DCI format and a UL grant DCIformat for any UE may include an information area or an informationfield indicating the specific modulation and coding scheme (MCS) indexcorresponding to the specific modulation and coding scheme (MCS)information. This information field may be an MCS index field. A formatof the physical downlink control channel indicating an MCS index for thephysical downlink shard channel and a format of the physical downlinkcontrol channel indicating an MCS index for the physical uplink shardchannel may be different from each other.

At least one of the two or more MCS tables may be an MCS table based ona higher modulation order including 64QAM or 256QAM, and another of theMCS tables may be an MCS table based on a lower modulation orderincluding QPSK or 16QAM.

For example, in the case of an MCS table optimized for maximizing thetransmission rate, such as the eMBB, an MCS table may be configuredbased on higher order modulation. For example, in the case of an MCStable for reliability-critical data, such as in the URLLC, an MCS tablemay be configured based on lower order modulation. That is, according tothe target BLER values, as a corresponding target BLER is higher, an MCStable having an MCS index may be configured based on a higher ordermodulation scheme such as 64QAM, 256QAM, or 1024QAM. As a target BLER islower, another MCS table having an MCS index may be configured based ona lower order modulation scheme such as QPSK, or 16 QAM may beconstructed.

A base station may implicitly signal information for selecting one ofthe two or more MCS tables through DL allocation DCI for the PDSCH andUL grant DCI for the PUSCH. The UE derives one of two or more MCStables, which have been signaled implicitly, through the DL allocationDCI for the PDSCH and the UL grant DCI for the PUSCH.

One of the two or more MCS tables may be determined by an RNTI valuescrambled with a CRC of the physical downlink control channel (PDCCH).The RNTI may be a new MCS-C-RNTI or a new MCS-CS-RNTI that isadditionally allocated for the URLLC other than a typical C-RNTI and atypical CS-RNTI.

For example, the information for selecting one of two or more MCS tablesmay be implicitly determined by a RNTI for PDCCH decoding of the UE.That is, in a case where such a new MCS table for the URLLC isconfigured for any UE, the base station may allocate a new RNTI for thenew MCS table, i.e., an MCS-C-RNTI or an MCS-CS-RNTI through higherlayer signaling. The UE may derive information for selecting one of twoor more MCS tables based on the new RNTI, i.e., the MCS-C-RNTI or theMCS-CS-RNTI.

Specifically, in addition to scheduling control information based on anMCS table defined for providing the typical eMBB service, i.e., theC-RNTI or the CS-RNTI allocated for UE-specific DL allocation DCI or ULgrant DCI transmission/reception, i) scheduling control information maybe separately defined based on an MCS table newly defined for the URLLC,i.e., the new RNTI (e.g., the MCS-C-RNTI or the MCS-CS-RNTI) forUE-specific DL allocation DCI or UL grant transmission/reception, andii) one of two or more MCS tables may be selected based on this newlydefined information.

As another method of selecting one of two or more MCS tables, an MCStable to be applied may be selected for each search space configured forany UE.

One of the two or more MCS tables may be determined according to a typeof search space through which physical downlink control channel (PDCCH)transmission is performed. The type of search space may be a UE-specificsearch space.

That is, the MCS table may be implicitly configured based on each searchspace kind/type (e.g., CS or UE-specific SS) through performing thephysical downlink control channel (PDCCH) transmission.

In the determining S1220, the UE determines the specific MCS informationusing the specific MCS index and one of two or more MCS tables.

For example, when the physical data channel is a physical downlink shardchannel (PDSCH), the base station may encode the physical downlink shardchannel (PDSCH) based on the specific MCS information. The UE decodesthe physical downlink shard channel (PDSCH) based on the specific MCSinformation.

For example, when the physical data channel is a physical uplink shardchannel (PUSCH), the UE encodes the physical uplink shard channel(PDSCH) based on the specific MCS information. The UE transmits thisphysical uplink shared channel (PUSCH) to the base station. The basestation receives this physical uplink shared channel (PUSCH) from theUE.

FIG. 13 is a block diagram illustrating a base station according to anembodiment of the present disclosure.

Referring to FIG. 13, a base station 1300 according to an embodimentincludes a controller 1310, a transmitter 1320, and a receiver 1330.

The controller 1310 controls the overall operation of the base station1300 for performing a method in which a separate MCS table is configuredfor each target BLER, as a method for configuring a MCS and a TBS in theNR required to perform the above-described embodiments of the presentdischarge.

The transmitter 1320 and the receiver 1330 are used to transmit to andreceive, from a UE, signals, messages, and data necessary for carryingout the present disclosure described above.

A UL grant DCI format for the UE may include an information area or aninformation field indicating a specific modulation and coding scheme(MCS) index corresponding to specific modulation and coding scheme (MCS)information. This information field may be an MCS index field.

At least one of two or more MCS tables may be an MCS table based on ahigher modulation order including 64QAM or 256QAM, and another of theMCS tables may be an MCS table based on a lower modulation orderincluding QPSK or 16QAM.

For example, in the case of an MCS table optimized for maximizing thetransmission rate, such as the eMBB, an MCS table may be configuredbased on higher order modulation. For example, in the case of an MCStable for reliability-critical data, such as in the URLLC, an MCS tablemay be configured based on lower order modulation. That is, according totarget BLER values, as a target BLER is higher, an MCS table having anMCS index may be configured based on a higher order modulation schemesuch as 64QAM, 256QAM, or 1024QAM. As a target BLER is lower, anotherMCS table having an MCS index may be configured based on a lower ordermodulation scheme such as QPSK or 16 QAM.

The base station may implicitly signal information for selecting one oftwo or more MCS tables through UL grant DCI for a PUSCH.

One of two or more MCS tables may be determined by an RNTI valuescrambled with a CRC of a physical downlink control channel (PDCCH). TheRNTI may be a new MCS-C-RNTI or a new MCS-CS-RNTI that is additionallyallocated for the URLLC other than a typical C-RNTI and a typicalCS-RNTI.

For example, the information for selecting one of two or more MCS tablesmay be implicitly determined by a RNTI for PDCCH decoding of the UE.That is, when such a new MCS table for the URLLC is configured for anyUE, a new RNTI for the new MCS table, i.e., an MCS-C-RNTI or anMCS-CS-RNTI may be allocated. The controller 1310 may scramble a CRC ofthe physical downlink control channel (PDCCH) with the new RNTI, e.g.,the MCS-C-RNTI or the MCS-CS-RNTI.

Specifically, in addition to scheduling control information based on anMCS table defined for providing the typical eMBB service, i.e., theC-RNTI or the CS-RNTI allocated for UE-specific DL allocation DCI or ULgrant DCI transmission/reception, i) scheduling control information maybe separately defined based on an MCS table newly defined for the URLLC,i.e., the new RNTI (e.g., the MCS-C-RNTI or the MCS-CS-RNTI) forUE-specific DL allocation DCI or UL grant transmission/reception, andii) one of two or more MCS tables may be selected based on this newlydefined information.

As another method of selecting one of two or more MCS tables, an MCStable to be applied may be selected for each search space configured forany UE.

One of the two or more MCS tables may be determined by a type of searchspace through which physical downlink control channel (PDCCH)transmission is performed. The type of search space may be a UE-specificsearch space.

That is, the MCS table may be implicitly configured by each search spacekind/type (e.g., CS or UE-specific SS) through which the physicaldownlink control channel (PDCCH) transmission is performed.

The receiver S1120 receives the physical uplink shard channel (PUSCH)modulated based on specific MCS information determined using thespecific MCS index and one of the two or more MCS tables.

That is, the UE determines the specific MCS information using thespecific MCS index and one of two or more MCS tables. The UE encodes thephysical uplink shard channel (PUSCH) based on the specific MCSinformation.

The UE transmits this physical uplink shared channel (PUSCH) to the basestation. The receiver 1330 receivers this physical uplink shared channel(PUSCH) from the UE.

FIG. 14 is a block diagram illustrating a UE according to an embodimentof the present disclosure.

Referring to FIG. 14, a UE 1400 according to another embodiment includesa receiver 1410, a controller 1420, and a transmitter 1430.

The receiver 1410 receives downlink control information and data,messages through a corresponding channel from a base station.

The controller 1420 controls the overall operation of the UE 1400 forperforming a method in which a separate MCS table is configured for eachtarget BLER, as a method for configuring a MCS and a TBS in the NRrequired to perform the above-described embodiments of the presentdischarge.

The transmitter 1430 transmits uplink control information and data,messages through a corresponding channel to the BS.

A physical data channel may be a physical downlink data/shard channel(PDSCH) or a physical uplink data/shard channel (PUSCH).

As described above, a downlink allocation DCI format and an uplink grantDCI format for a UE may include an information area or an informationfield indicating the specific modulation and coding scheme (MCS) indexcorresponding to the specific modulation and coding scheme (MCS)information. This information field may be an MCS index field. A formatof a physical downlink control channel indicating an MCS index for thephysical downlink shard channel and a format of a physical downlinkcontrol channel indicating an MCS index for the physical uplink shardchannel may be different from each other.

At least one of two or more MCS tables may be an MCS table based on ahigher modulation order including 64QAM or 256QAM and another of the MCStables may be an MCS table based on a lower modulation order includingQPSK or 16QAM.

For example, in the case of an MCS table optimized for maximizing thetransmission rate, such as the eMBB, an MCS table may be configuredbased on higher order modulation. For example, in the case of an MCStable for reliability-critical data, such as in the URLLC, an MCS tablemay be configured based on lower order modulation. That is, according totarget BLER values, as a target BLER is higher, an MCS table having anMCS index may be configured based on a higher order modulation schemesuch as 64QAM, 256QAM, or 1024QAM. As a target BLER is lower, anotherMCS table having an MCS index may be configured based on a lower ordermodulation scheme such as QPSK or 16 QAM.

The base station may implicitly signal information for selecting one ofthe two or more MCS tables through DL allocation DCI for the PDSCH andUL grant DCI for the PUSCH. The controller 1420 derives one of two ormore MCS tables, which have been signaled implicitly, through the DLallocation DCI for the PDSCH and the UL grant DCI for the PUSCH.

One of two or more MCS tables may be determined by an RNTI valuescrambled with a CRC of the physical downlink control channel (PDCCH).The RNTI may be a new MCS-C-RNTI or a new MCS-CS-RNTI that isadditionally allocated for the URLLC other than a typical C-RNTI and atypical CS-RNTI.

The controller 1420 selects one of two or more MCS tables based on theRNTI value scrambled with the CRC of the physical downlink controlchannel (PDCCH), i.e., the MCS-C-RNTI or the MCS-CS-RNTI.

For example, information for selecting one of two or more MCS tables maybe implicitly determined by a RNTI for PDCCH decoding of the UE. Thatis, in a case where such a new MCS table for the URLLC is configured forany UE, a new RNTI for the new MCS table, i.e., an MCS-C-RNTI or anMCS-CS-RNTI may be allocated. The controller 1429 may derive informationfor selecting one of two or more MCS tables based on the new RNTI, i.e.,the MCS-C-RNTI or the MCS-CS-RNTI.

Specifically, in addition to scheduling control information based on anMCS table defined for providing the typical eMBB service, i.e., theC-RNTI or the CS-RNTI allocated for UE-specific DL allocation DCI or ULgrant DCI transmission/reception, i) scheduling control information maybe separately defined based on an MCS table newly defined for the URLLC,i.e., the new RNTI (e.g., the MCS-C-RNTI or the MCS-CS-RNTI) forUE-specific DL allocation DCI or UL grant transmission/reception, andii) one of two or more MCS tables may be selected based on this newlydefined information.

As another method of selecting one of two or more MCS tables, an MCStable to be applied may be selected for each search space configured forany UE.

One of the two or more MCS tables may be determined by a type of searchspace through which physical downlink control channel (PDCCH)transmission is performed. The type of search space may be a UE-specificsearch space.

That is, the MCS table may be implicitly configured by each search spacekind/type (e.g., CS or UE-specific SS) through which the physicaldownlink control channel (PDCCH) transmission is performed.

That is, the controller 1420 determines specific MCS information using aspecific MCS index and one of two or more MCS tables.

For example, when the physical data channel is a physical downlink shardchannel (PDSCH), the base station may encode the physical downlink shardchannel (PDSCH) based on the specific MCS information. The controller1420 decodes the physical downlink shard channel (PDSCH) based on thespecific MCS information.

For example, when the physical data channel is the physical uplink shardchannel (PUSCH), the UE encodes the physical uplink shard channel(PDSCH) based on the specific MCS information. The transmitter 1430transmits this physical uplink shared channel (PUSCH) to the basestation. The base station receives this physical uplink shared channel(PUSCH) from the UE.

The embodiments described above may be supported by the standarddocuments disclosed in at least one of the wireless access systems IEEE802, 3GPP and 3GPP2. That is, the steps, configurations, and parts notdescribed in the present embodiments for clarifying the technical ideamay be supported by standard documents described above. In addition, allterms disclosed herein may be described by the standard documentsdescribed above.

The embodiments described above may be implemented by various means. Forexample, the embodiments of the present disclosure may be implemented byhardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according toembodiments may be implemented by one or more of application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs)(Field Programmable Gate Arrays), a processor, a controller, amicrocontroller, a microprocessor, or the like.

In the case of an implementation by firmware or software, the methodaccording to the embodiments may be implemented in the form of anapparatus, a procedure, or a function for performing the functions oroperations described above. The software code may be stored in a memoryunit and driven by the processor. The memory may be located inside oroutside the processor, and may exchange data with the processor byvarious well-known means.

The terms “system”, “processor”, “controller”, “component”, “module”,“interface”, “model”, “unit”, and the like, described above maygenerally refer to computer-related entity hardware, a combination ofhardware and software, software, or software in execution. For example,components described above may be, but are not limited to, a processdriven by a processor, a processor, a controller, a control processor,an entity, an execution thread, a program and/or a computer. Forexample, an application running on a controller, controller or processorcan be a component. One or more components can be included within aprocess and/or thread of execution, and a component can be placed on onesystem or be disposed on more than one system.

The features, structures, configurations, and effects described in thepresent disclosure are included in at least one embodiment but are notnecessarily limited to a particular embodiment. A person skilled in theart can apply the features, structures, configurations, and effectsillustrated in the particular embodiment embodiments to another one ormore additional embodiment embodiments by combining or modifying suchfeatures, structures, configurations, and effects. It should beunderstood that all such combinations and modifications are includedwithin the scope of the present disclosure. Accordingly, the embodimentsof the present disclosure are intended to be illustrative rather thanlimiting, and the scope of the present invention is not limited by theseembodiments. The scope of protection of the present disclosure is to beconstrued according to the claims, and all technical ideas within thescope of the claims should be interpreted as being included in the scopeof the present invention.

1-20. (canceled)
 21. A method of receiving control information for aphysical data channel by a wireless device, the method comprising:receiving, through a physical downlink control channel, the controlinformation indicating a specific modulation and coding scheme (MCS)index corresponding to specific MCS information for the physical datachannel; and determining the specific MCS information used for thephysical data channel using the specific MCS index and one MCS tablefrom a plurality of MCS tables, wherein the one MCS table comprisesmodulation order information and a target code rate corresponding to thespecific MCS index, wherein the one MCS table is configured based on alower modulation order, which is lower than 256 quadrature amplitudemodulation (QAM), and wherein the one MCS table is associated with aspecific RNTI for both a physical downlink shared channel and a physicaluplink shared channel performing a code block group basedretransmission.
 22. The method of claim 21, wherein the specific RNTI isan MCS-C(Cell)-radio network temporary identifier (RNTI).
 23. The methodof claim 21, wherein the specific RNTI is allocated by a base stationthrough a higher layer signaling.
 24. The method of claim 21, whereinthe one MCS table is associated with the reception of the physicaldownlink control channel in a certain search space.
 25. The method ofclaim 24, wherein the certain search space is a user equipment(UE)-specific search space.
 26. The method of claim 21, wherein a formatof the physical downlink control channel indicating the specific MCSindex for the physical downlink shared channel is different from aformat of the physical downlink control channel indicating the specificMCS index for the physical uplink shared channel.
 27. A wireless devicecomprising: a receiver configured to receive control informationindicating a specific modulation and coding scheme (MCS) indexcorresponding to specific MCS information for a physical data channelthrough a physical downlink control channel; and a controller configuredto determine the specific MCS information used for the physical datachannel using the specific MCS index and one MCS table from a pluralityof MCS tables, wherein the one MCS table comprises modulation orderinformation and a target code rate corresponding to the specific MCSindex, wherein, based on the determined specific MCS information, thephysical data channel is transmitted or received, wherein the one MCStable is configured based on a lower modulation order, which is lowerthan 256 quadrature amplitude modulation (QAM), and wherein the one MCStable is associated with a specific RNTI for both a physical downlinkshared channel and a physical uplink shared channel performing a codeblock group based retransmission.
 28. The wireless device of claim 27,wherein the specific RNTI is an MCS-C (Cell)-radio network temporaryidentifier (RNTI).
 29. The wireless device of claim 27, wherein thespecific RNTI is allocated by a base station through a higher layersignaling.
 30. The wireless device of claim 27, wherein the one MCStable is associated with the reception of the physical downlink controlchannel in a certain search space.
 31. The wireless device of claim 30,wherein the certain search space is a user equipment (UE)-specificsearch space.
 32. The wireless device of claim 27, wherein a format ofthe physical downlink control channel indicating the specific MCS indexfor the physical downlink shared channel is different from a format ofthe physical downlink control channel indicating the specific MCS indexfor the physical uplink shared channel.
 33. A method of transmittingcontrol information for a physical data channel by a base station, themethod comprising: determining specific modulation and coding scheme(MCS) information used for the physical data channel; and afterdetermining the specific MCS information, transmitting, through aphysical downlink control channel, the control information indicating aspecific modulation and coding scheme (MCS) index corresponding tospecific MCS information for the physical data channel, wherein thespecific MCS information is determined based on one MCS table from aplurality of MCS tables, wherein the one MCS table comprises modulationorder information and a target code rate corresponding to the specificMCS index, wherein, based on the determined specific MCS information,the physical data channel is transmitted or received, wherein the oneMCS table is configured based on a lower modulation order, which islower than 256 quadrature amplitude modulation (QAM), and wherein theone MCS table is associated with a specific RNTI for both a physicaldownlink shared channel and a physical uplink shared channel performinga code block group based retransmission.
 34. The method of claim 33,wherein the specific RNTI is an MCS-C(Cell)-radio network temporaryidentifier (RNTI).
 35. The method of claim 33, wherein the specific RNTIis allocated through a higher layer signaling.
 36. The method of claim33, wherein the one MCS table is associated with the transmission of thephysical downlink control channel in a certain search space.
 37. Themethod of claim 36, wherein the certain search space is a user equipment(UE)-specific search space.
 38. The method of claim 33, wherein a formatof the physical downlink control channel indicating the specific MCSindex for the physical downlink shared channel is different from aformat of the physical downlink control channel indicating the specificMCS index for the physical uplink shared channel.